Application: plasma-desktop (4.11.11)
KDE Platform Version: 4.13.3
Qt Version: 4.8.6
Operating System: Linux 3.13.0-52-generic x86_64
Distribution: Ubuntu 14.04.2 LTS

-- Information about the crash:
- What I was doing when the application crashed:
run firefox
right click
wait till its bar on task panel diapears
pressed "show a launcher when not running for firefox

-- Backtrace:
Application: Plasma Desktop Shell (plasma-desktop), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f957d96b7c0 (LWP 2156))]

Thread 3 (Thread 0x7f95545e9700 (LWP 2157)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f957661fffb in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#2  0x00007f9576620039 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#3  0x00007f9570ecb182 in start_thread (arg=0x7f95545e9700) at pthread_create.c:312
#4  0x00007f957d26c47d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7f94ce127700 (LWP 2158)):
#0  0x00007f9579d5aadc in do_gettime (frac=0x7f94ce126b70, sec=0x7f94ce126b68) at tools/qelapsedtimer_unix.cpp:129
#1  qt_gettime () at tools/qelapsedtimer_unix.cpp:144
#2  0x00007f9579e36f05 in updateCurrentTime (this=0x7f94c8003130) at kernel/qeventdispatcher_unix.cpp:354
#3  QTimerInfoList::timerWait (this=0x7f94c8003130, tm=...) at kernel/qeventdispatcher_unix.cpp:460
#4  0x00007f9579e3567c in timerSourcePrepareHelper (src=<optimized out>, timeout=0x7f94ce126c24) at kernel/qeventdispatcher_glib.cpp:143
#5  0x00007f9579e35725 in timerSourcePrepare (source=<optimized out>, timeout=<optimized out>) at kernel/qeventdispatcher_glib.cpp:176
#6  0x00007f95707b968d in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#7  0x00007f95707b9f03 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#8  0x00007f95707ba0ec in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#9  0x00007f9579e357be in QEventDispatcherGlib::processEvents (this=0x7f94c80008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:436
#10 0x00007f9579e070af in QEventLoop::processEvents (this=this@entry=0x7f94ce126de0, flags=...) at kernel/qeventloop.cpp:149
#11 0x00007f9579e073a5 in QEventLoop::exec (this=this@entry=0x7f94ce126de0, flags=...) at kernel/qeventloop.cpp:204
#12 0x00007f9579d03c5f in QThread::exec (this=this@entry=0x1888560) at thread/qthread.cpp:537
#13 0x00007f9579de8823 in QInotifyFileSystemWatcherEngine::run (this=0x1888560) at io/qfilesystemwatcher_inotify.cpp:265
#14 0x00007f9579d0632f in QThreadPrivate::start (arg=0x1888560) at thread/qthread_unix.cpp:349
#15 0x00007f9570ecb182 in start_thread (arg=0x7f94ce127700) at pthread_create.c:312
#16 0x00007f957d26c47d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f957d96b7c0 (LWP 2156)):
[KCrash Handler]
#6  data (this=0x450044004b9a60) at /usr/include/qt4/QtCore/qsharedpointer_impl.h:587
#7  TaskManager::TaskItem::task (this=0x3a6c740) at ../../../libs/taskmanager/taskitem.cpp:135
#8  0x00007f955609ed4b in TaskManager::ToggleLauncherActionImpl::toggleLauncher (this=0x3a8fd20) at ../../../libs/taskmanager/taskactions.cpp:469
#9  0x00007f9579e20c1e in QObject::event (this=0x3a8fd20, e=<optimized out>) at kernel/qobject.cpp:1194
#10 0x00007f957919d4f2 in QAction::event (this=<optimized out>, e=<optimized out>) at kernel/qaction.cpp:1187
#11 0x00007f95791a1e2c in QApplicationPrivate::notify_helper (this=this@entry=0xfa9d00, receiver=receiver@entry=0x3a8fd20, e=e@entry=0x3bdf790) at kernel/qapplication.cpp:4567
#12 0x00007f95791a84a0 in QApplication::notify (this=this@entry=0xf91090, receiver=receiver@entry=0x3a8fd20, e=e@entry=0x3bdf790) at kernel/qapplication.cpp:4353
#13 0x00007f957aacdd1a in KApplication::notify (this=0xf91090, receiver=0x3a8fd20, event=0x3bdf790) at ../../kdeui/kernel/kapplication.cpp:311
#14 0x00007f9579e084dd in QCoreApplication::notifyInternal (this=0xf91090, receiver=receiver@entry=0x3a8fd20, event=event@entry=0x3bdf790) at kernel/qcoreapplication.cpp:953
#15 0x00007f9579e0bb3d in sendEvent (event=0x3bdf790, receiver=0x3a8fd20) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#16 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0xf211f0) at kernel/qcoreapplication.cpp:1577
#17 0x00007f9579e0bfe3 in QCoreApplication::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0) at kernel/qcoreapplication.cpp:1470
#18 0x00007f9579e35f83 in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#19 postEventSourceDispatch (s=0xfa7500) at kernel/qeventdispatcher_glib.cpp:287
#20 0x00007f95707b9e04 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#21 0x00007f95707ba048 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#22 0x00007f95707ba0ec in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#23 0x00007f9579e357a1 in QEventDispatcherGlib::processEvents (this=0xf22af0, flags=...) at kernel/qeventdispatcher_glib.cpp:434
#24 0x00007f9579243bb6 in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#25 0x00007f9579e070af in QEventLoop::processEvents (this=this@entry=0x7ffe580b7cf0, flags=...) at kernel/qeventloop.cpp:149
#26 0x00007f9579e073a5 in QEventLoop::exec (this=this@entry=0x7ffe580b7cf0, flags=...) at kernel/qeventloop.cpp:204
#27 0x00007f9579e0cb79 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1225
#28 0x00007f95791a037c in QApplication::exec () at kernel/qapplication.cpp:3828
#29 0x00007f957d57367c in kdemain (argc=1, argv=0x7ffe580b7f48) at ../../../../plasma/desktop/shell/main.cpp:126
#30 0x00007f957d193ec5 in __libc_start_main (main=0x4006e0 <main(int, char**)>, argc=1, argv=0x7ffe580b7f48, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffe580b7f38) at libc-start.c:287
#31 0x000000000040070e in _start ()

Reported using DrKonqi